Qt 5.10.0 MySQL 驅動程序無法在 Fedora 27 上編譯

Question

我最近將我的機器更新到最新版本的 Fedora Linux 27 和 Qt 5.10.0。 Qt 框架是使用離線安裝程序 qt-opensource-linux-x64-5.10.0 安裝的，我通常這樣做。 在安裝過程中檢查了所有選項，以確保安裝了所有插件、源代碼和庫。 這也是我通常在更新后重新安裝 Qt 的方式。

現在的問題是沒有加載MySQL驅動程序

QSqlDatabase: QMYSQL driver not loaded

以前在 Qt 5.8 或 5.7 等早期版本中，通過鏈接正確版本的 libmysqlclient.so 或從 Src 目錄重新編譯它，可以解決此問題。 但這現在根本不起作用。

所以這里是需要MySQL的Qt程序的ldd

linux-vdso.so.1 (0x00007ffc13709000)
    libmysqlclient.so.21 => /usr/lib64/mysql/libmysqlclient.so.21 (0x00007f59732cb000)
    libzmq.so.5 => /usr/local/lib/libzmq.so.5 (0x00007f5973045000)
    libQt5WebEngineWidgets.so.5 => /opt/Qt/Qt5.10.0/5.10.0/gcc_64/lib/libQt5WebEngineWidgets.so.5 (0x00007f5972e04000)
    libQt5PrintSupport.so.5 => /opt/Qt/Qt5.10.0/5.10.0/gcc_64/lib/libQt5PrintSupport.so.5 (0x00007f5972b97000)
    libQt5Widgets.so.5 => /opt/Qt/Qt5.10.0/5.10.0/gcc_64/lib/libQt5Widgets.so.5 (0x00007f597235e000)

可以看出這需要已經安裝的最新版本的mysql libmysqlclient.so.21 庫

這是/opt/Qt/Qt5.10.0/5.10.0/gcc_64/plugins/sqldrivers/libqsqlmysql.so的ldd輸出

linux-vdso.so.1 (0x00007ffeb8bf8000)
    libQt5Sql.so.5 => /opt/Qt/Qt5.10.0/5.10.0/gcc_64/plugins/sqldrivers/./../../lib/libQt5Sql.so.5 (0x00007f60cd408000)
    libQt5Core.so.5 => /opt/Qt/Qt5.10.0/5.10.0/gcc_64/plugins/sqldrivers/./../../lib/libQt5Core.so.5 (0x00007f60cccba000)
    libpthread.so.0 => /lib64/libpthread.so.0 (0x00007f60cca9b000)
    libmysqlclient.so.18 => not found
    libstdc++.so.6 => /lib64/libstdc++.so.6 (0x00007f60cc715000)
    libm.so.6 => /lib64/libm.so.6 (0x00007f60cc3c0000)
    libgcc_s.so.1 => /lib64/libgcc_s.so.1 (0x00007f60cc1a9000)
    libc.so.6 => /lib64/libc.so.6 (0x00007f60cbdc6000)
    libz.so.1 => /lib64/libz.so.1 (0x00007f60cbbaf000)
    libicui18n.so.56 => /opt/Qt/Qt5.10.0/5.10.0/gcc_64/plugins/sqldrivers/./../../lib/libicui18n.so.56 (0x00007f60cb716000)
    libicuuc.so.56 => /opt/Qt/Qt5.10.0/5.10.0/gcc_64/plugins/sqldrivers/./../../lib/libicuuc.so.56 (0x00007f60cb35e000)
    libicudata.so.56 => /opt/Qt/Qt5.10.0/5.10.0/gcc_64/plugins/sqldrivers/./../../lib/libicudata.so.56 (0x00007f60c997b000)
    libdl.so.2 => /lib64/libdl.so.2 (0x00007f60c9777000)
    libgthread-2.0.so.0 => /lib64/libgthread-2.0.so.0 (0x00007f60c9575000)
    libglib-2.0.so.0 => /lib64/libglib-2.0.so.0 (0x00007f60c9261000)
    /lib64/ld-linux-x86-64.so.2 (0x00007f60cd863000)
    libpcre.so.1 => /lib64/libpcre.so.1 (0x00007f60c8fee000)

很明顯，這表示 libmysqlclient.so.18 => not found 因為安裝了最新版本的 libmysqlclient.so.21。

現在，當我嘗試重新編譯驅動程序時，我遇到了一個重復的問題

qsql_mysql.cpp:235:9: error: ‘my_bool’ does not name a type; did you mean ‘_Bool’?

這是我所做的

    cd /opt/Qt/Qt5.10.0/5.10.0/Src/qtbase/src/plugins/sqldrivers/mysql

/opt/Qt/Qt5.10.0/5.10.0/gcc_64/bin/qmake "INCLUDEPATH+=/usr/include/mysql" "LIBS+=-L/usr/lib64/mysql"  mysql.pro

make

Make 因一個奇怪的錯誤而失敗

 g++ -c -pipe -O2 -std=c++1z -fvisibility=hidden -fvisibility-inlines-hidden -fno-exceptions -Wall -W -Wvla -Wdate-time -D_REENTRANT -fPIC -DQT_NO_NARROWING_CONVERSIONS_IN_CONNECT -DQT_NO_CAST_TO_ASCII -DQT_NO_CAST_FROM_ASCII -DQT_NO_EXCEPTIONS -D_LARGEFILE64_SOURCE -D_LARGEFILE_SOURCE -DQT_NO_DEBUG -DQT_PLUGIN -DQT_SQL_LIB -DQT_CORE_LIB -I. -I/opt/Qt/Qt5.10.0/5.10.0/gcc_64/include/QtSql/5.10.0 -I/opt/Qt/Qt5.10.0/5.10.0/gcc_64/include/QtSql/5.10.0/QtSql -I/opt/Qt/Qt5.10.0/5.10.0/gcc_64/include/QtCore/5.10.0 -I/opt/Qt/Qt5.10.0/5.10.0/gcc_64/include/QtCore/5.10.0/QtCore -I/opt/Qt/Qt5.10.0/5.10.0/gcc_64/include -I/opt/Qt/Qt5.10.0/5.10.0/gcc_64/include/QtSql -I/opt/Qt/Qt5.10.0/5.10.0/gcc_64/include/QtCore -I.moc -isystem /usr/include/mysql -I/opt/Qt/Qt5.10.0/5.10.0/gcc_64/mkspecs/linux-g++ -o .obj/qsql_mysql.o qsql_mysql.cpp
qsql_mysql.cpp:235:9: error: ‘my_bool’ does not name a type; did you mean ‘_Bool’?
         my_bool nullIndicator;
         ^~~~~~~
         _Bool
qsql_mysql.cpp: In constructor ‘QMYSQLResultPrivate::QMyField::QMyField()’:
qsql_mysql.cpp:231:28: error: class ‘QMYSQLResultPrivate::QMyField’ does not have any field named ‘nullIndicator’
             : outField(0), nullIndicator(false), bufLength(0ul),
                            ^~~~~~~~~~~~~
qsql_mysql.cpp: In member function ‘bool QMYSQLResultPrivate::bindInValues()’:
qsql_mysql.cpp:430:28: error: ‘struct QMYSQLResultPrivate::QMyField’ has no member named ‘nullIndicator’
         bind->is_null = &f.nullIndicator;
                            ^~~~~~~~~~~~~
qsql_mysql.cpp: In member function ‘virtual QVariant QMYSQLResult::data(int)’:
qsql_mysql.cpp:641:15: error: ‘const struct QMYSQLResultPrivate::QMyField’ has no member named ‘nullIndicator’
         if (f.nullIndicator)
               ^~~~~~~~~~~~~
qsql_mysql.cpp: In member function ‘virtual bool QMYSQLResult::isNull(int)’:
qsql_mysql.cpp:734:35: error: ‘const struct QMYSQLResultPrivate::QMyField’ has no member named ‘nullIndicator’
        return d->fields.at(field).nullIndicator;
                                   ^~~~~~~~~~~~~
qsql_mysql.cpp: In member function ‘virtual bool QMYSQLResult::exec()’:
qsql_mysql.cpp:987:13: error: ‘my_bool’ was not declared in this scope
     QVector<my_bool> nullVector;
             ^~~~~~~
qsql_mysql.cpp:987:13: note: suggested alternative: ‘_Bool’
     QVector<my_bool> nullVector;
             ^~~~~~~
             _Bool
qsql_mysql.cpp:987:20: error: template argument 1 is invalid
     QVector<my_bool> nullVector;
                    ^
qsql_mysql.cpp:1001:20: error: request for member ‘resize’ in ‘nullVector’, which is of non-class type ‘int’
         nullVector.resize(values.count());
                    ^~~~~~
qsql_mysql.cpp:1008:25: error: invalid types ‘int[int]’ for array subscript
             nullVector[i] = static_cast<my_bool>(val.isNull());
                         ^
qsql_mysql.cpp:1008:41: error: ‘my_bool’ does not name a type; did you mean ‘_Bool’?
             nullVector[i] = static_cast<my_bool>(val.isNull());
                                         ^~~~~~~
                                         _Bool
qsql_mysql.cpp:1009:46: error: invalid types ‘int[int]’ for array subscript
             currBind->is_null = &nullVector[i];
                                              ^
qsql_mysql.cpp:1105:17: error: expected ‘;’ before ‘update_max_length’
         my_bool update_max_length = true;
                 ^~~~~~~~~~~~~~~~~
qsql_mysql.cpp:1114:72: error: ‘update_max_length’ was not declared in this scope
             mysql_stmt_attr_set(d->stmt, STMT_ATTR_UPDATE_MAX_LENGTH, &update_max_length);
                                                                        ^~~~~~~~~~~~~~~~~
qsql_mysql.cpp: In member function ‘virtual bool QMYSQLDriver::open(const QString&, const QString&, const QString&, const QString&, int, const QString&)’:
qsql_mysql.cpp:1316:5: error: ‘my_bool’ was not declared in this scope
     my_bool reconnect=false;
     ^~~~~~~
qsql_mysql.cpp:1316:5: note: suggested alternative: ‘_Bool’
     my_bool reconnect=false;
     ^~~~~~~
     _Bool
qsql_mysql.cpp:1334:21: error: ‘reconnect’ was not declared in this scope
                     reconnect = true;
                     ^~~~~~~~~
qsql_mysql.cpp:1334:21: note: suggested alternative: ‘connect’
                     reconnect = true;
                     ^~~~~~~~~
                     connect
qsql_mysql.cpp:1415:13: error: ‘reconnect’ was not declared in this scope
         if (reconnect)
             ^~~~~~~~~
qsql_mysql.cpp:1415:13: note: suggested alternative: ‘connect’
         if (reconnect)
             ^~~~~~~~~
             connect
make: *** [Makefile:806: .obj/qsql_mysql.o] Error 1

說真的，我已經使用 Qt 多年了，以前我在設置 MySQL 驅動程序時從未遇到過這個問題。 奇怪的是，現在機器更新了所有最新版本。

請讓我知道我該如何解決這個問題。 現在已經在互聯網上搜索了近一個星期，但沒有解決此錯誤的方法。 我嘗試過的一切都以錯誤告終

qsql_mysql.cpp:235:9: error: ‘my_bool’ does not name a type; did you mean ‘_Bool’?

Answer 1

所以終於找到了解決辦法。 我不得不對 Fedora 27 進行全新安裝，這次安裝了 Fedora 25 中以前的 MySQL 版本

dnf install https://dev.mysql.com/get/mysql57-community-release-fc25-9.noarch.rpm dnf install mysql-community-server

還安裝了所有其他依賴項。 之后像往常一樣從離線包安裝 Qt 5.10.0。 然后重新編譯 sqldrivers，它運行得很順利，根本沒有顯示任何錯誤。

所以我猜MySQL 8.0目前與 Qt 不兼容。

Answer 2

我在 QT 論壇上找到了另一個人的解決方案： https : //forum.qt.io/topic/114022/different-versions-of-qt-with-different-versions-of-mysql

只需打開文件 qsql_mysql.cpp 並添加“typedef bool my_bool;” 就在初始標頭包含定義所在的位置之后。

那么你應該很高興去。